Jet therapy method



March 22, 1955 R, P, SCHERER 2,704,542

JET THERAPY METHOD Filed Feb. 21, 1949 Pre sa are 1N VENTOR.

United States Patent O JET THERAPY METHOD Robert Pauli Scherer, Detroit, Mich., assignor to R. P. Scherer Corporation, Detroit, Mich., a corporation of Michigan Application February 21, 1949, Serial No. 77,517

Claims. (Cl. 12S- 173) This invention relates to a method of hypodermic therapy or injection, which is properly called jet therapy or jet injection as distinguished from syringe and needle type injections.

One object of the invention is to provide a method of successfully performing jet therapy with assured control of the depth of injection so that the injection is made at the desired subcutaneous level whether intradermal, in the fatty tissues, or in the fascia or the muscle.

Another object is to provide the method steps which consist of first hydraulically sealing the edge of a jet oriiice in relation to the epidermis, then projecting a jet from the jet orifice at sufficient velocity to puncture the epidermis and then penetrate and form a channel to the desired subcutaneous level, following which medicament or the like is injected to that level and dispersed laterally through the tissues of the body.

Still another object is to provide a method which contemplates the projection of the jet from the orice in two distinct stages, the irst or initial stage occurring under high pressure which produces high velocity thereof and involving a relatively small volume of medicament serving mainly to establish a channel through the epidermis and the underlying tissues to the desired depth, and the second stage being contiguous to the first and at a reduced pressure effective to feed the medicament through the previously established channel to the depth established by the rst stage but substantially without causing the penetration to go deeper whence substantially lateral dilfusion only then takes place.

A further object is to provide a method of jet therapy in which the depth of injection is regulated by the intensity and duration of an initial penetrating jet, and injection at the level to which the jet penetrated is then accomplished by a follow-through jet which is continued until the desired quantity of liquid has been injected at that level.

Still a further object is to provide a method which permits exact control of the quantity of medicament injected, that is insures that all the medicament supplied r in an ampule is injected without any wastage on the exterior of the epidermis.

With these and other objects in view, my invention consists in a jet therapy method for attaining the objects contemplated, as hereinafter more fully set forth and pointed out in my claims, the steps for my method being illustrated generally in the accompanying drawings, which are not to be taken as limiting of the invention, but merely with a view to illustrate possible apparatus to enable others skilled in the art to apply my method under varying conditions of practical use.

Figure l is an enlarged cross sectional view of a medicament containing ampule described in detail in my copending application Serial No. 93,282, filed May 14, 1949, which may be used in the practice of the herein disclosed method, the figure showing the ampule held tightly against a patients body in order to effect a hydraulic seal between the epidermis and the edge of a jet orifice in the ampule.

Figure 2 is a similar sectional view showing an initial high-pressure penetrating jet opening a channel down to a desired depth in the body tissues.

Figure 3 is a similar sectional view showing the penetrating jet of Figure 2 terminated and a follow-through jet nearly completed to perform the desired injection 2,704,542 Patented Mar. 22, 1955 at the level to which the cutting jet of Figure 2 penetrated, and

Figure 4 is a pressure-time curve to illustrate the pressures involved in the operation of the ampule to accomplish the penetrating and follow-through jet operations of my jet therapy method.

On the accompanying drawing I have used the reference character A to indicate an ampule which may be charged with a suitable liquid 10 to be injected such as medicament. The ampule A has a cylindrical wall 12 and a rounded end 14. The end 14 is perforated by a jet orifice 16. The orifice 16 is preferably about .002 to .005 in diameter to secure the desired jet action that effects puncture of the epidermis and thereafter penetration to a desired depth which by distending the tissues underlying the epidermis opens a channel for a followthrough jet.

Above the medicament 10 is a follower 18 of resilient material, such as rubber, and it is to be propelled toward the jet orifice 16 by means of a primary plunger 20 and a secondary plunger 22. The plunger 22 is tubular in character.

Theampule A is adapted to be held in a hypo jet injector of the kind disclosed in my copending application Serial No. 94,579, filed May 2l, 1949, and the plungers 2t) and 22 are parts of such holder or injector and are driven by a spring or other suitable means to provide a two-stage jet action. Said application also discloses a single plunger and two springs of different strength which act in succession to accomplish two-stage jet action.

The first step in my method consists of placing the ampule A tightly in contact with a patients body, at the desired location for an injection. The epidermis is indicated at 24, the underlying dermal layer (corium) at 26, the fat tissues at 28, the fascia at 30 and the muscle at 32. The ampule is pressed tightly against the epidermis to form a hydraulic seal between the epidermis and the edge of the jet orifice 16, as illustrated in Figure l. This is an important preliminary to the injecting operation and if not properly accomplished, may result in loss of a considerable proportion of the medicament 10 as well as cause a painful multiple injection due to liquid between the ampule and the epidermis acting like a lubricant on the skin surface and permitting the ampule to skid laterally during the injection which produces a slit in the patients skin.

The next step in the jet injection operation is to produce a high enough pressure on the liquid 10 that a jet 34 will project from the jet orilice 16, puncture the skin layers 24 and 26 and penetrate to the desired subcutaneous depth, such action producing a channel to that depth by compressing the tissues surrounding the jet. The initial high pressure penetrating jet is accomplished by moving the primary plunger 20 by means of a spring as in my above mentioned hypo jet injector application Serial No. 94,579 as, for example until the jet reaches the fascia 30. The fascia libers are considerably more resistant to the passage of the jet than the fat cells 28 and accordingly some variation in pressure can be had and still obtain the desired result. By increasing the pressure a considerable extent, however, the jet may be made to penetrate on through the fascia and enter the muscle 32, if that is the desirable location for the injection.

After the high-pressure penetrating jet 34 opens a channel indicated at 36 to the desired depth it is necessary to reduce from high pressure to a lower pressure in order to substantially terminate further penetration and to then merely feed liquid through the channel 36 to the depth that the jet penetrated and allow the liquid to disperse laterally as indicated for instance in Figure 3 at 10a.

As far as I have been able to determine, the high pressure jet penetration is in the manner of a needle of ininitesimal diameter followed by a spreading or distending action of the tissues in all directions away from the axis of the channel established by the penetrating jet and this occurs without the removal of any tissues that would cause trauma. The action is rather a stretching of the tissues with subsequently nearly complete recovery to close the channel due to the elasticity in the tissues after the injection has been made. Apparently the channel 1s formed by the penetrating jet pushing aside the tissues, thus establishing the desired channel through which the medicament can be supplied at a relatively lower pressure than that required for the penetrating or channel forming action.

The injection in Fig. 3 is in the fascia layer. Most of the liquid will be disposed in this layer as the initial high velocity of the jet 34 causes merely a penetrating and channel opening action without any appreciable dispersion because the velocity is so high. By lowering the velocity as a result of lowering the pressure, dispersion as to the position a takes place as additional liquid is fed through the channel or passageway 36.

The lower pressure on the medicament 10 is produced by moving both the primary plunger and the secondary plunger 22 simultaneously after the position of Figure 2 is assumed. By using a single spring to first move the plunger 20 only, high pressure is had because of its small area, and lower pressure is thereafter had upon simultaneous movement of the two plungers because of the larger piston area then being acted upon by the same` spring. Two-stage operation in the way just described or by having two springs act successively on a single plunger is shown graphically in Figure 4 wherein the pressure curve a, b, c, d, e, f is a result of the following:

The pressure rises slightly from a to b as play in the mechanism is taken up and the central portion of the follower 18 then starts to move toward the position of Figure 2 whereupon the pressure builds up substantially instantaneously, or at least rapidly, from b to c. It reaches a peak at c after having passed a point b which represents the pressure at the time the jet actually punctures the epidermis. From b to c the jet 34 penetrates down to the layer as illustrated in Figure 2 and then the pressure sharply drops because the spring picks up the secondary plunger 22 and must thereafter operate both plungers together. The effective area of the secondary plunger and the primary plunger together is greater than the area of the primary plunger alone. Accordingly from d to e low pressure for the follow-through jet obtains with the final position of the parts as in Figure 3 occurring when the plungers stop moving. Pressure then of course sharply drops off to zero as indicated by the section e, f of the curve.

The depth of the injection may be controlled by means disclosed in my hypo jet injector application, Serial No. 94,579, the depth of jet penetration being decreased by use of a weaker spring that doesnt build up to such a high peak pressure as indicated, for instance to only c' in Figure 4 The pressure then reduces to the point d and low pressure for the follow-through jet begins to come into play. On the other hand the jet may be made to penetrate deeper as into the muscle 32 by using a higher initial pressure indicated by the peak c which may be produced by the same spring with the addition of impact or by a stronger spring as explained in the application just referred to.

If a small quantity of liquid is to be injected, the low pressure follow-through step of the method may be omitted but for most injections of practical volume it is desirable to first produce a penetrating jet for opening a channel to the desired depth and then reduce the pressure to provide a follow-through jet, otherwise the continued high pressure jet would produce a curve such as shown from c to e to f in Figure 4 during which the piercing or penetrating jet would be in operation from b to a point after e thereby causing a progressively deeper injection without appreciable lateral dispersion of the medicament. This could even cause the jet to pass all the way through a patients limb and strike the epidermis on the opposite side. The control of the piercing jet and the use of a follow-through jet thereafter at a lower pressure are accordingly important features of my method for most types of injections.

The period of time the penetrating jet is in operation can be changed by changing the travel of the plunger 20 before the plunger 22 begins to move and the depth of the channel formed by the penetrating jet can thereby be accurately controlled. The depth can also be variably decreased by directing the jet at various angles instead of at right angles to the skin surface but in all instances long as the high pressure obtains and then the liquid disperses at the level of the bottom of the channel upon a drop to the lower follow-through pressure. Conversely, the depth of penetration can be increased by pressing the ampule more tightly against the skin which displaces the fatty tissue and positions the ampule orifice closer to the desired injection level so that the jet discharge penetrates more deeply. This is particularly useful in connection with intra-muscular injections and is not painful because of the end of the ampule being rounded.

My method may be varied to some extent without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modifications or use of mechanical equivalents which may be reasonably included within their scope.

I claim as my invention:

l. A method of operating a jet injector having a quantity of liquid in a container thereof which is provided with an orifice, comprising the steps of bringing said orifice into intimate contact with an organic cellular body, initially displacing through only the area of the body opposed to said orifice a portion of said liquid with jet penetrating velocity, whereby a hole is temporarily formed in said area through which said jet enters and penetrates the cells of the body to a predetermined depth, and then displacing the remaining portion of the liquid through the jet opened hole in the body with reduced velocity and thereby with substantially no further penetrating action, whereby lateral injection is effected at said predetermined depth.

2. A method of operating an injecting instrument which has a container therein provided with a jet orifice, comprising the steps of placing said container tightly against an object to provide a hydraulic seal between the edge of said orifice and the object, displacing liquid from the container through the jet orifice at a pressure sufficiently high to produce a jet velocity which causes the jet to penetrate the object and open a channel therein to a desired depth, including the steps of continuing the high pressure acting on the jet until the jet has reached such desired depth, and abruptly stopping the high pressure and thereafter continuing said jet at a lower pressure after the high pressure action has been exerted and until the liquid has been dispersed at said desired depth.

3. A method of operating a jet injector having a quantity of liquid in a container thereof which is provided with an orifice, comprising the steps of bringing said orifice into intimate contact with an organic cellular body with a pressure of sufficient magnitude that a sealed connection between the edge of said orifice and the body is provided which will withstand without leakage the pres-- sure produced by a penetrating jet, initially displacing through only the area of the body opposed to said orifice, a portion of said liquid with high pressure to produce jet penetrating velocity whereby a hole is temporarily formed in said area through which said jet enters, continuing at substantially said high pressure the penetrating jet action until the jet penetrates the cells of the body to a predetermined depth, and then lowering the pressure radically and continuing the displacing of the liquid through the jet opened hole in the body at said lowered pressure, whereby substantially no further penetrating action takes place and lateral injection is effected at said predetermined depth.

4. A method of operating a jet injector having a quantity of liquid in a container thereof which is provided with an orifice, comprising the steps of bringing the edge of said orifice into intimate contact with an organic cellular body, primarily displacing through only the area of the body opposed to said orifice, a portion of said liquid with jet penetrating velocity thereby to temporarily form in said area an opening through which said jet enters and penetrates the cells of the body to a predetermined depth, secondarily displacing the remaining portion of the liquid through the jet formed opening in the body with a substantially constant but radically lower follow-through velocity to stop further penetrating action and accomplish lateral injection at said predetermined depth, and tertiarily terminating the displacing action.

5. The method of injecting fluids into the human body comprising the steps of placing a container of an injecting instrument having a jet orifice tightly against the epithe jet remains in jet form for penetrating purposes so 8l dermis to provide a hydraulic seal between the edge of References Cited in the le of this patent UNITED STATES PATENTS Cook Dec. 9, 1930 Lockhart June 22, 1943 Lockhart June 22, 1943 Lockhart July 31, 1945 Lockhart Apr. 16, 1946 

